The present invention relates to diester amine adducts, to a process for the preparation of these compounds and to their use.
The diester amine adducts of this invention correspond to formula 
wherein
R1, R2, R3, R4 are each independently of one another C4-C22alkyl; C2-C22alkenyl; or C5-C7-cycloalkyl;
X1 and X2 are each independently of the other hydrogen, C1-C4alkyl; C2-C4hydroxyalkyl or C2-C4hydroxyhaloalkyl;
Y is a radical of formula (1b) 
A1 is C2-C3alkylene or 2-hydroxy-n-propylene;
X3 is hydrogen; C1-C4alkyl, C2-C4hydroxyalkyl; or C2-C4hydroxyhaloalkyl; 
is an asymmetrical carbon atom in the R- or S-configuration, wherein, if
C1=R, C2=R;
C1=S, C2=S; and
C1=R; C2=S;
m1 is 1 or 2; and
n is an integer from 1 to 4;
p is 0 or 1;
which adduct may be in the form of a free base, acid, acid salt or quatemary ammonium salt.
The diester amine adducts are stereochemically uniform compounds in the (SS)-, (RR)- or (RS)-configuration, i.e. compounds which can be represented by formulae 
C1-C22Alkyl is a straight-chain or branched alkyl radical, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, amyl, isoamyl or tert-amyl, heptyl, octyl, isooctyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl or octadecyl or eicosyl.
C2-C22Alkenyl is, for example, allyl, methallyl, isopropenyl, 2-butenyl, 3-butenyl, isobutenyl, n-penta-2,4-dienyl, 3-methyl-but-2-enyl, n-oct-2-enyl, n-dodec-2-enyl, iso-dodecenyl, n-dodec-2-enyl or n-octadec-4-enyl.
C5-C7Cycloalkyl is typically cyclopentyl, cycloheptyl or, preferably, cyclohexyl.
C2-C4Hydroxyalkyl is, for example, 2-hydroxyethyl or 4-hydroxy-n-butyl.
C2-C4Hydroxyhaloalkyl is typically 1-chloro-2-hydroxyethyl.
Preferred diester amine adducts of formula (1) are those, wherein
A1 is C2-C3alkylene;
m is 2; and
p is 0.
Particularly preferred diester amine adducts of formula (1) are those, wherein X1 and X2 are hydrogen and very particularly preferably those, wherein R1, R2, R3 and R4 are C4-C2alkyl.
Examples of diester diamine adducts of this invention are the compounds of formulae 
The novel diester amine adducts, which are stereochemically uniform with respect to the C1 and C2 atoms (see formula (1)), are prepared by methods known per se by reacting an aminodicarboxylic acid of formula 
with an excess of the relevant alcohol under the action of gaseous HCl or thionyl chloride in a one-pot reaction. Such a process is disclosed, inter alia, in C.A. 62, 11911g (1965). The corresponding diester amine adducts can be converted to the corresponding diester amine adducts of formula (1) by reacting the resultant aminodicarboxylates of formula 
with a dihalogen compound of formula
Halxe2x80x94(A1)mxe2x88x921Hal.xe2x80x83xe2x80x83(1f)
The entire course of the reaction can be represented as follows: 
Tetraesters which are stereochemically uniform with respect to the amino carboxylic acid frameare also obtained by reacting, for example, the diaminotetracarboxylic acid of formula (1g) or the salts of this acidwith thionyl chloride and an alcohol to the corresponding ester compound of formula (1f): 
The thionyl chloride is added dropwise usually in the temperature range from xe2x88x9270 to 80xc2x0, preferably from xe2x88x9210 to 30xc2x0 C. In the further course of the reaction the temperature is raised up to 200xc2x0 C., the preferred temperature range being from 40 to 80xc2x0 C.
Thionyl chloride is usually used in excess. In principle, thionyl chloride can also be replaced with gaseous hydrogen chloride.
After the reaction is complete, the hydrochlorides of the tetraesters may, if required, be isolated in the form of crystalline compounds and then recrystallised.
The alcohol component is used as solvent for the reaction (high excess).
The starting compound can be a water-containing tetracarboxylic acid, e.g. EDDS having a water content of about 20%.
Monoesters of the aminodicarboxylic acid can be obtained in good yields by a commonly known process by reacting the carboxylic acid with the relevant alcohol.
Mixtures of the compounds of formulae (1a), (1b) and (1c) are obtained by first esterifying maleic anhydride with an alcohol to the corresponding diester and then reacting 2 mol of the respective diester with diamine.
For many applications it is also possible to replace the stereochemically uniform products with mixtures of the stereoisomers of formulae (1a), (1b) and (1c) which are also obtained in the above manner.
The stereochemically uniform compounds of formula (1) and the diester amine adducts of formula 
are precursors of compounds having pronounced complex-forming properties. Under physio-logical conditions, the ester groups can be split by esterases. The chemical hydrolysis is carried out in aqueous medium in the presence of OHxe2x88x92 or H+ ions. Compounds are obtained wherein R1=R2=R3=R4=H, for example N,Nxe2x80x2-ethylenediamine disuccinic acid (EDDS). Such compounds are thus able to effectively bind heavy metal ions such as iron, zinc, magnesium or copper ions and to prevent metal-initiated oxidations.
In contrast to the free acids or the salts of the acids (R1=R2=R3=R4=H), the compounds of formula (1) are readily soluble in organic solvents, fats and oils, new fields of application being thus obtained. Said compounds are therefore suitable as additives in food and beverages products which are susceptible to oxidation and which are inclined to spoil or to become rancid. The foods susceptible to oxidation are, in particular, compounds or compositions containing olefinic double bonds.
Owing to their complex-forming properties, the novel diester amine adducts can also be used for removing undesirable calcium depositions, boiler scale and rust. They are usually used to this purpose in alkaline derusting and decalcification baths.
The novel compounds are furthermore used as additives in liquids for cooling-water circuits for preventing and dissolving calcium depositions.
The novel adducts are also used in personal-care products, for example in creams, lotions, body-care products, such as deodorants, soaps or shampoos and ointments, for preventing oxidation, rancidness, turbidity and the like.
It is possible to achieve, in particular, a soft handle effect on hair.
Furthermore, the novel diamine adducts are used as bleaching stabilisers, e.g. for sodium perborate, in detergents or in textile or paper bleaching. Heavy metal traces, for example iron, copper or magnesium, are present in detergent formulations, in water and in textile and paper materials and catalyse the degradation of sodium perborate as well as of other bleaches present in the detergent. The novel compounds bind these metal ions and prevent the undesirable degradation of the bleaching system both during storage of the corresponding detergent as well as in the washing liquor. The effectivity of the bleaching system is thus improved and fibre damage is prevented. In addition, other sensitive detergent components, such as enzymes, fluorescent whitening agents and fragrances are advantageously protected against oxidative degradation.
The novel adducts can also be used in cleaning agents and detergents for removing metal ions and as preservatives. In liquid cleaning formulations, the novel compounds may advantageously be used in a concentration of 0.05 to 15% by weight, based on the entire weight of the formulation.
The novel diester amine adducts can also be advantageously used in the textile industry for removing traces of heavy metal during production and when dyeing natural and synthetic fibres. They prevent spotty and streaky dyeings on textile material, bad wettability and unlevelness.
The novel diester amine adducts of formula (1) are also very suitable as soft handle agents for organic fibre materials such as paper or, in particular, textile fibre materials. Particularly good soft handle effects are achieved in the case of loose fibres, yams, in particular wovens or knits of natural cellulose, e.g. cotton, or of polyacrylonitrile. These adducts can also be used to impart soft handle to fibre materials of synthetic polyamides or regenerated cellulose. Good soft handling effects are already obtained in fabric coatings of 0.1 to 1%, preferably of 0.2 to 0.6%.
Treatment of fibres is effected by treating the fibre materials with a preferably aqueous formulation, e.g. with an aqueous solution or emulsion of these adducts, applying the adducts to the fibres and then drying them. It is convenient to use 0.5 to 5%, preferably 1 to 3%, of a c. 20% emulsion or solution, based on the weight of the fibre materials to be finished. The aqueous formulations can be applied to the fibres by impregnation processes customarily used in the industry (e.g. padding or exhaust process). Solutions in organic solvents are often used via spraying.
In the same manner it is possible to treat paper webs with the novel adducts by spraying or by a dipping process, which also results in a fine and supple soft handle.
The novel diester amine adducts of formula (1) can also be used as antistatic agents for textiles, in particular for polyester fabrics.
In the paper industry, the novel compounds can be used for eliminating heavy metal/iron ions. Iron depositions on paper result in so-called hot spots as soon as the oxidative, catalytic degradation of the cellulose starts.
The novel diester amine adducts are also suitable as catalysts for organic syntheses, such as for the aerial oxidation of paraffins or for hydroformylating olefins to alcohols.
The novel diester amine adducts can be used in any desired form, for example as powder, granulate, paste, liquid formulation, tablet, capsule, pill, suspension or gel.
If the novel adducts are used e.g. as body-care products, then such a product comprises 0.01 to 15, preferably 0.5 to 10% by weight, based on the total weight of the composition, of the diester amine adduct of formula (1) or (2) as well as cosmetically compatible assistants.
Depending on the body-care product""s form of it comprises other components in addition to the diester amine adduct, for example sequestrants, colourants, perfume oils, thickeners or consistency regulators, emollients, UV absorbers, skin protectives, antioxidants, additives improving the mechanical properties, such as dicarboxylic acid and/or the Al, Zn, Ca, Mg salts of C4-C22fatty acids.
Owing to their good solubility in oil and alcohol, the novel diester amine adducts can be incorporated in the corresponding formulations without any difficulties.
A soap has, for example, the following composition:
0.01 to 5% by weight of the compound of formula (1) or (2),
0.3 to 1% by weight of titanium dioxide,
1 to 10% by weight of stearic acid,
ad 100% soap base, for example the sodium salts of tallow fatty acid and of coconut fatty acid or glycerols.
A shampoo has, for example, the following composition:
0.01 to 5% by weight of the compound of formula (1) or (2),
12.0% by weight of sodium-laureth-2-sulfate,
4.0% by weight of cocamidopropylbetaine,
3.0% by weight of NaCl, and water ad 100%.
A deodorant has, for example, the following composition:
0.01 to 5% by weight of the compound of formula (1) or (2),
60% by weight of ethanol,
0.3% by weight of perfume oil, and water ad 100%.
The following non-limitative Examples illustrate the invention in more detail. The SS-DDS used has a water content of about 20%